Etiqueta: fractal dimension

Research on electroencephalogram (EEG) asymmetries and anxiety proneness has recently spread to emotion regulation capabilities. We studied whether attentional control (AC), a temperamental construct related to emotional regulation, was associated with asymmetrical patterns of resting EEG activity at the frontal and parietal regions, reflected not only in the α frequency band (8-13 Hz) but also in higher bands β1 (13-20 Hz) and β2 (20-30 Hz). Self-reports of AC and trait anxiety, and resting EEG recordings, were obtained from 58 healthy participants. Correlational analysis showed that lower levels of self-reported AC were associated with less α, β1, and β2 powers in the left parietal cortex, while no significant relationships were found between the AC and EEG oscillations in the prefrontal cortex. The role of the left and right parietal lobes in the attentional processes is discussed.

The aim of our study was to characterize brain dynamics of affective modulation of somatosensory processing in chronic pain. We hypothesized that chronic pain patients will show abnormal EEG activity under negative mood conditions compared to healthy controls. Nineteen patients with chronic pain and 21 healthy subjects participated in the experiment. Multiscale entropy, fractal dimension, event-related potentials, and fast Fourier transform were used to analyze EEG data. A significant enhancement of entropy was found in pain patients at P4 compared to P3. Analysis of fractal dimension also revealed significantly higher values at P4 than P3 when pain patients were viewing unpleasant pictures. By contrast, no significant differences due to hemisphere or affective condition were found on nonlinear measures for healthy controls. Analyses of somatosensory ERPs showed that P50 amplitudes elicited by pleasant pictures were more reduced in chronic pain patients than in healthy controls. Finally, we observed that EEG band power was lower in pain patients than in healthy controls, in particular for theta and beta bands over sensorimotor cortices and temporal regions when viewing pleasant images. These findings suggest that sustained pain seems to be accompanied by an abnormal activation and dynamic of brain networks related to emotional processing of somatosensory information in chronic pain. Furthermore, our findings suggest that both linear and nonlinear measures of EEG time series may contribute to the understanding of brain dysfunction in chronic pain.